Exemplary embodiments of the invention generally relate to lubrication systems, and more particularly, to an indicator for determining the amount of lubrication in a lubrication system of an aircraft.
A sealed gearbox having meshing gears, shaft bearing, and other components is provided with a continuous flow of lubricant in excess of that required for cooling. Lubricant within the gearbox is subject to churning where the lubricant hits the gears and to windage resulting from action of the gears throwing the lubricant. The churning and windage, as well as the viscous drag of the lubricant, results in heat generation. The amount of lubricant in the gearbox is critical for proper operation. For example, if the gearbox includes an excessive amount of lubricant, churning may occur which ultimately increases the temperature of the gearbox. If the gearbox has too little lubricant, the lubricant will degrade prematurely. Therefore, maintaining a proper amount of lubricant is important for a long-lasting and uninterrupted operation of transmissions.
Conventional systems include an indicator mechanism for determining the amount of lubricant within the system, such as a sight glass or dipstick for example. When the system is not positioned on a flat surface, however, the level of lubricant indicated by the indicator mechanism is affected, because the level is being measured outside of the system. For example, an indicator mechanism for a gearbox of an aircraft drive system having an acceptable level of lubricant may indicate that the system includes too much or too little lubricant depending on the incline of the aircraft.